✶[tk] became [kk] or [kt] or [sk]; [tk] > [kk]

✶[tk] became [kk] or [kt] or [sk]; [tk] > [kk]
@@@ Q examples: (ek)koiru- and ekkes-, as well as possibly ekkaira and ekkoita-

From Lokyt:

P < PP: S. ephed-, ephel, aphed-
TK < KK: Q. accar, aquet-; T. okko; S. achar, echad-, echor, echuir, echui(w), ochui, Aracchír
TK < KT: Q. ehtele, ehtelu-, ahtar; S. eithel
Plus the whole S. stop mutation of p-, k- apparently shows TP/TK > PP/KK as well.

References ✧ PE17/166; PE19/87; VT47/42

Phonetic Rule Elements

[tk] > [kk] ✧ PE19/87 (tk > kk)
[tk] > [kt] ✧ PE17/166 (tk > kt; frequently in Quenya)
[tk] > [sk] ✧ VT47/42 (tk > sk)
[tp] > [pp]

Phonetic Rule Examples

etkantē > ekkantē tk > kk ✶et-kantē > S. echant ✧ PE17/42
etkat- > ekkat- tk > kk ✶et-kat- > S. echad- ✧ PE17/42
etpel > eppel tp > pp ✶et-pel > eppel > S. ephel ✧ PE17/65
etpet- > eppet- tp > pp AT. et-pet > S. ephed ✧ PE17/167

ᴹ✶[tk] became [kk] or [kt]; [tk] > [kk]

GS/§4.10 @@@ also tp > pp? Example: S. ephel

Phonetic Rule Elements

[tk] > [kk]
[tk] > [kt]
[tp] > [pp]

Phonetic Rule Examples

etkat- > ekkat- tk > kk ᴹ✶et-kat > N. echedi ✧ Ety/KAT
etkuiwē > ekkuiwē tk > kk ᴹ✶et-kuiwē > N. echui(w) ✧ Ety/KUY
etkelē > ektelē tk > kt ᴹ✶et-kelē > ᴹ✶ektele ✧ Ety/KEL
etkelu- > ektelu- tk > kt ᴹ✶et-kelu > ᴹQ. ehtelu- ✧ PE22/103
etpele > eppele tp > pp ᴹ✶Et-pele > eppele > N. Ephel ✧ WR/137